As a member of a voting coalition comprised of rank and file Republicans, Democrats, Independents, and Libertarians, all focused on fiscal responsibility and limited government, Libertartians will be making the largest philosophical contribution.
My unfortunate use of "even Libertarians" referred to their relative size as a voting block, not the impact they are having on this election. Indeed, the minimizing of social wedge issues which permits Democrats and Independents to focus on fiscal issues and limited goverment principles over social wedge issues is very Libertarian.

With a few inexperienced Republican Senate candidates struggling, some analysts are suggesting that the Tea Party damaged the party's chances in November by helping weak candidates win primary elections. That may be true in the Senate, but the GOP has always been more likely to regain its majorit...

The body of your analysis is quite good, the title threw me off a little, I was expecting a negative piece on the Tea Party.
I think a more appropriate title would be "Is the Tea Party Really Hurting the GOP?" I realize that title might not attract as many readers, but that is the real question you are answering.
One thing that is currently hard to quantify is the impact the Tea Party is having on playing down emotional, social wedge issues? This is where the long term impact of the Tea Party will be measured.
Stressing fiscal conservatism and limited government against the backdrop of debt-driven social unrest in Europe strengthens the Tea Party message. If a coalition of voters is formed that include Democrats, Independents, and even Libertarians that value fiscal conservatism and limted government over sensitive social wedge issues, the U.S. political landscape will be redefined.

With a few inexperienced Republican Senate candidates struggling, some analysts are suggesting that the Tea Party damaged the party's chances in November by helping weak candidates win primary elections. That may be true in the Senate, but the GOP has always been more likely to regain its majorit...